Digital predistortion for dual-input Doherty amplifiers

This paper presents a digital predistortion technique for dual-input Doherty power amplifiers. The proposed technique utilizes both RF inputs of the main and peak amplifiers in the digital predistorter. The effectiveness of the resulting dual-input predistorter is evaluated on a two-way Doherty amplifier operating at 2.14 GHz with 53.5 dBm peak output power. The experimental results demonstrate that the dual-input approach outperforms the conventional single-input predistortion technique by ~3 dB in terms of adjacent channel leakage ratio.